Tunable Synthesis of Polysubstituted Pyrroles via Silver-Catalyzed (3 + 2) Cycloaddition of α,β-Unsaturated Nitroketones with Isocyanides

A controlled silver-catalyzed cycloaddition reaction of α,β-unsaturated nitroketones with isocyanides has been developed, facilitating the construction of polysubstituted pyrroles. This protocol addresses the issue of side reactions associated with the high reactivity of the aldehyde group in conventional reactions by employing a synergistic strategy for the protection and deprotection of the aldehyde group. Additionally, the nitrone moiety stabilizes the cycloaddition transition state through spatial electronic effects and is spontaneously deprotected to yield aromatization products.